Monthly returns, IBM common stock. Jan. 1961-Dec. 1967.
#see also NYSE.1, ATT.1
   0.072513
   0.062500
   0.029630
   0.027338
   0.027521
  -0.026612
   0.024185
   0.067967
   0.035611
   0.092007
  -0.011745
  -0.001724
  -0.063903
  -0.007841
  -0.007914
  -0.147818
  -0.133811
  -0.135669
   0.140752
   0.025840
  -0.107886
  -0.021216
   0.153902
  -0.021330
   0.086538
  -0.054277
   0.053158
   0.101544
   0.031267
  -0.085909
  -0.004011
   0.025892
   0.016301
   0.092920
  -0.015182
   0.044822
   0.069033
   0.052122
   0.044376
  -0.040387
   0.054910
  -0.006250
  -0.031447
  -0.043831
  -0.009081
  -0.037801
  -0.014881
  -0.007273
   0.095238
   0.019509
  -0.003291
   0.067694
  -0.011340
  -0.041841
   0.045851
   0.044885
   0.027054
   0.040000
  -0.012195
  -0.049524
  -0.006012
   0.041331
   0.001942
   0.080426
  -0.022018
  -0.029635
  -0.027817
  -0.056200
  -0.009360
   0.045669
   0.135843
  -0.011968
   0.075370
   0.079099
   0.048837
   0.100887
  -0.035234
   0.067024
   0.020603
  -0.013589
   0.097048
   0.082535
   0.033024
   0.024510
